The rapid expansion of legal markets for medical and adult cannabis products in the United States and other countries has spurred an increase in the number and variety of cannabis-containing products along with a widening variety of consumption or delivery methods in recent years. Use of smoking or vaping apparatus to deliver aerosolized cannabinoid bioactive compounds in inhaled smoke or vapor remains a popular consumption method, since the inhaled cannabinoid compounds are readily absorbed in pulmonary tissues. Inhalation provides a more rapid onset of pharmacological action and peak plasma levels than ingestion, although various types of edible or orally consumed products have become popular as well. The pharmacokinetics achieved via pulmonary delivery are comparable to those achieved via intravenous administration, but inhalation is a much less invasive approach that is also more convenient for self-medication.
For many consumers or patients using cannabis products as a medicine, traditional inhalation-based delivery methods involving combustion may be undesirable due to various potential risks or negative side-effects of smoking. In addition, smoking can be inconvenient and can pose challenges to consistent dosing and discrete administration. Various methods of inhalation delivery using electronic vaporizers partially address some of the negative aspects of combustion-based smoking. However, plant matter, concentrate, and liquid product vaporizers are subject to various other inconveniences, including cleaning, maintenance, charging, etc. Other inhalation delivery systems such as metered dose inhalers have been described that address certain shortcomings of inhalation-based delivery methods relying on combustion or vaporization; however, such products have been narrowly THC-focused, perform poorly due to clogging or other issues, or are devoid of other aspects associated with cannabis consumption, such as providing the consumer or patient with an ability to select various cannabinoid profiles and/or other product attributes that affect a consumer's experience. Therefore, improved metered dose inhaler formulations and systems are desirable.